Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C233/00—Carboxylic acid amides
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C255/00—Carboxylic acid nitriles
  • C07C255/49—Carboxylic acid nitriles having cyano groups bound to carbon atoms of six-membered aromatic rings of a carbon skeleton

Definitions

• 2,6-dichlorobenzamide is produced by the removal through heating of water and hydrochloric acid from 1- hydroxy, 2,2,6,6 tetrachlorocyclohexane-carbonamide. Catalysts such as zinc chloride and iodine may be employed.
• the 2,6-dichlorobenzamide is an intermediate for the production of 2,6-dichlorobenzonitrile, a known herbicide.
• This invention relates to a new and improved method of preparing 2,6-dichlorobenzamide.
• the compound 2,6-dichlorobenzonitrile has excellent herbicidal properties and is useful as an active constituent in weed killing compositions.
• a principal method of preparing 2,6-dichlorobenzonitrile consists in the dehydration of 2,6-dichlorobenzamide.
• the cost of producing 2,6-dichlorobenzamide is therefore a key factor in the cost of 2,6-dichlorobenzonitrile. It is therefore a principal object of this invention to prepare the compound 2,6-dichlorobenzamide in a new and inexpensive manner.
• 2,6- dichlorobenzamide may be manufactured in a high yield and in an inexpensive manner from the novel compound 1 hydroxy, 2,2,6,6-tetrachlorocyclohexanecarbonamide, Formula 1.
• the compound 2,2,6,G-tetrachlorocyclohexanonecyanehydrine is obtained by treating 2,2,6,6-tetrachlorocyclohexanone with hydrocyane.
• the 2,2,6,6-tetrachlorocyclohexanone may be prepared in a known manner by the chlorination of cyclohexanol.
• 2-6-dichlorobenzamide may be prepared in an inexpensive manner and in a high yield by the removal, by heating, of water and hydrochloric acid from l-hydroxy, 2,2,6,6- tetrachlorocyclohexane-carbonamide and thereby form an aromatic ring.
• the aromatizing reaction of the cyclo-aliphatic carbonamide may be carried out by dry heating of the substance the said reaction is preferably carried out, in order to avoid additional reactions, in a solvent.
• Non-polar solvents such as, for example, chlorinated or non-chlorinated aliphatic or aromatic hydrocarbons, for example xylene, monochlorobenzene, toluene, benzene, octane and ethylene chloride are preferred. Exceptionally good results are obtained with trichlorobenzene as a solvent.
• Suitable dehydrating catalysts are for example, iodine, hydriodic acid, oxalic acid, tin chloride and phthalic acid anhyride. Optimum results are obtained when using zinc chloride as the catalyst. It has been unexpectedly found that the reactions may in this case be carried out at a temperature below 150 without phenols being formed as a by-product. Preferably from 0.5 to 1 mol of zinc chloride per molecule of the carbonamide are used.
• the resulting 2,6-dichlorobenzamide if desired after previous purification, may be converted by known methods into 2,6-dichlorobenzonitrile.
• the concentrated residue which according to an LR. analysis, contains less than 5% of 2,2,6,6 tetrachloro-cyclohexanone, has a melting point from 125 C. to 136 C. dependent on the rate at which benzene is removed.
• a product having a melting point from 102 C. to 105 C. is obtained by boiling the residue in benzene for 10 minutes and then distilling off the benzene at ordinary pressure.
• the two modifications have in solution identical LR. spectra.
• the melting point varies from 104 C. to 107 C. after recrystallization from a solvent mixture composed of 20% of benzene and of petroleum ether (80 C. to C).
• 2,6-DICHLOBO-BENZONITRILE For the manufacture of the nit-rile, use may be made of the crude oil-like reaction product without previously removing the zinc chloride.
• the conversion of the amide into the nitrile in itself is a known reaction for which several dehydrating agents may be used such, for example, as 1PCl P POC1
• 1PCl P POC1 By heating the nonpurified oil-like reaction products at about 105 C. for 1 hour, after adding gms. of POCl an amount of 12 g. of 2,6-diohlorobenzonitrile is obtained after steam distillation.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Agricultural Chemicals And Associated Chemicals (AREA)

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ID=19754670

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Cited By (4)

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Citations (3)

• 0
  • NL NL292269D patent/NL292269A/xx unknown
• 1964
  • 1964-04-24 US US362496A patent/US3444196A/en not_active Expired - Lifetime
  • 1964-04-29 SE SE5364/64A patent/SE316462B/xx unknown
  • 1964-04-29 DK DK214864AA patent/DK108004C/da active
  • 1964-04-29 CH CH560264A patent/CH455735A/de unknown
  • 1964-04-30 GB GB18004/64A patent/GB1066811A/en not_active Expired
  • 1964-04-30 BR BR158848/64A patent/BR6458848D0/pt unknown
  • 1964-04-30 DE DEN24909A patent/DE1221622B/de active Pending
  • 1964-04-30 JP JP39024307A patent/JPS4935613B1/ja active Pending
  • 1964-04-30 AT AT384364A patent/AT247866B/de active
  • 1964-04-30 FR FR972972A patent/FR1397573A/fr not_active Expired
  • 1964-05-04 BE BE647498A patent/BE647498A/xx unknown

Patent Citations (3)

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